JPS5861504A - Method of producing paste for forming transparent conductive film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a paste for forming a transparent conductive film for forming a transparent conductive film made of a saponified metal into a desired shape on a substrate such as glass by screen printing and baking. .

It is well known that oxide films of cadmium, indium, tin, antimony, etc. formed on substrates such as glass, ceramic, and lamic are transparent and exhibit good conductivity, and are used in semiconductor devices and liquid crystal display devices. In recent years, the range of applications has been expanding, such as as transparent electrodes for electrochromic display devices, electroluminescent devices, etc., and conductive films for preventing icing on window glasses. The metal oxide transparent conductive film is formed by chemical spraying or vacuum evaporation of a transparent conductive film made of tin oxide, indium oxide, indium oxide-tin oxide, or tin oxide-antimony oxide on a substrate such as glass. There are those formed by the method and the screen printing method.

The chemical spray method can obtain a film with a relatively large area.
is advantageous, but to obtain fine and complex shapes,
Extra steps such as photo-etching are required and the process is not economical. The vacuum evaporation method has recently developed into a mass evaporation method, which has eliminated the need for photoetching, but it is not suitable for mass production because a large amount cannot be deposited at the same time. The clean printing method does not have such problems, can print and bake objects in the desired shape, and has the advantage that there is no need for waste liquid treatment associated with etching treatment. but,
Conventionally, the stability of the paste for forming a transparent conductive film itself was poor, resulting in poor workability during screen printing and large variations in the conductivity of the formed film.

The object of the present invention is to overcome the above-mentioned drawbacks, to provide a method for producing a paste for forming a transparent conductive film that can form a film with low resistance and good transparency, has high stability of the paste itself, and has a long pot life. be.

A feature of the present invention is that it focuses on an organic tin complex as a compound that provides a metal oxide film upon firing. Conventionally,
In this type of base, indium octylate (
Traditionally, indium organic acids with strong ionic bonding properties such as Cy Has Cot )s L have been mainly used, or organic indium complexes that are expensive to manufacture have been used, but when these organic indicum compounds are made into a paste, Since it has the disadvantage of being relatively easily chemically changed, such as by promoting gelation of the paste, it shortens the life of the paste itself and causes problems during screen printing.

Therefore, in the present invention, by using dimethyltin acedope (CH,)tsn(aCaC)t, tin optylate acedope, etc. as an organic tin complex, paste formation was successfully achieved. (CH3)2 Sn (acac)! decomposes thermally at temperatures above 400°C and becomes almost completely metal oxide at about 500°C, but it is difficult to make a film containing only tin oxide low in resistance, so a trace amount of antimony oxide is added to the formed film. It is common to adjust the resistance value by including it. That is,
An organic antimony compound that is calcined to form antimony oxide is required. Triphenylantimony, tetrabutoxyantimony, etc. can be used in consideration of their stability at room temperature and their ability to almost completely turn into antimony oxide at about 500°C.

Next, the viscosity agent and solvent necessary for pasting will be described.

First, as the viscosity agent, ethyl cellulose, nitrocellulose, acetyl cellulose, benzyl cellulose, etc. can be used. Next, regarding the solvent, it must have properties such as poor reaction resistance to organic tin complexes and organic antimony compounds, and good ability to dissolve the above-mentioned viscous agents. This solvent and a high boiling point alcohol such as -C12-ethylhexyl alcohol, benzyl alcohol, α-4-terpinenol, ethyl acetoacetate, benzyl acetate.

High boiling point esters such as methyl benzoate, dimethyl phthalate, diethyl phthalate, and dibutyl heptatalate.

High boiling point ketones such as acetonylacetone and isophorone, carpitol groups such as methylcarpitol, carpitol, butylcarpitol, dibutylcarpitol, carpitol acetate, etc. can be used. These f# media may be used alone or in combination of two or more.

Next, a method for manufacturing the paste will be explained. These four paste manufacturing methods are important in the present invention, and first,
A conventional method for manufacturing this type of paste will be described, and then a method for manufacturing the present invention will be described.

In the conventional method, (CH,)I Sn (acac)
The above-mentioned solvents are added to the phenylanthimose and the chicken, and the mixture is heated at a temperature of 1130 to 180° C. for 2 to 8 hours. Next, a cellulose compound as a viscosity agent is added and stirred using a stirring device. When a paste is made in this way, it gels violently, and while stirring, the viscosity of the paste increases until it completely turns into a gel.

Therefore, in the present invention, (cH,), t Sn (aCa
c) Weigh out *, add each of the above solvents to it, and add 180
Heat at a temperature of ~180°C. Next, a cellulose compound as a viscosity agent is added and stirred using a stirring device. The paste created in this way is referred to as A paste. Separately, triphenylantimony was weighed, each of the above solvents was added thereto, and the mixture was heated at a temperature of 180 to 180°C.
Heat for ~8 hours. The solution prepared in this manner is referred to as Solution B. Finally, paste A and a certain amount of liquid B are mixed and stirred to complete paste C.

The thus-prepared C paste is printed into the desired shape using a screen printing method, pre-dried at 180-170°C, and then baked at 500-600°C to obtain a transparent and highly conductive film. can.

Hereinafter, it will be explained in more detail with reference to examples. First, (CHs) * 8n (acac)1 was added to 15
F is weighed and placed in a separable flask, and then the following solvents are added: butylcarpitol 17Or, butyl cellosolve 85t, benzyl acetate 85f, and dimethyl phthalate 859, and heated at 180 to 180°C for 2 to 8 hours. After confirming that this solution is at room temperature, 60% of released nitrocellulose (manufactured by Taihei Kagaku Co., Ltd., product name H80) is added and heated for 5 to 8 hours using a stirring device to form A paste. It was created.

Preparation of Solution B Weigh 7.5 g of triphenylantimony and place it in a separable flask. Next, add 45% of butyl-carpitol.
5f, butyl cellosolve 28t, benzyl acetate 28t
9. Add dimethyl phthalate to each solvent of 2132,
Heat at 180-180°C for 2-8 hours. In this way, liquid B is prepared.

After creating paste A and liquid B as described above,
Paste and B liquid were mixed and stirred to complete C paste.

Here, FIG. 1 shows the results of examining the sheet resistance value of the transparent conductive film obtained by baking the C paste by changing the mixing ratio of the B liquid for adjusting the resistance value. This figure shows triphenylantimony (
Co Hs )s Sb dimethyltinacedope (C
H3)! 8n (acac)*, and has excellent conductivity.

The sheet resistance value was determined by screen printing C paste on a Pyrex glass plate at 150°C.

This was obtained by pre-drying for 20 minutes and then baking at 500°C for 80 minutes.1. The MW to be applied is 10θOA.The light transmittance of the coating that showed the minimum resistance value was determined by CT manufactured by JASCO Corporation.
When measured with a -25N spectrometer, as shown in the graph of Figure 2, the light wavelength in the visible light range was 400 nm to 800 nm.
The average value up to m was 97% or more.

As described above, in the present invention, a paste mainly composed of an organic tin complex such as dimethyltinacedope and a solution of an organic antimony compound such as triphenyl antimono are prepared separately, and the two are mixed to form a transparent conductive material. The present invention is characterized in that it is a paste for forming a transparent film. According to this invention, a film with low resistance and high transparency is formed, and furthermore, the stability of the paste itself is also good.

[Brief explanation of the drawing]

FIG. 1 is a sheet Sakai resistivity characteristic diagram of the transparent conductive coating obtained in the second embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the transmittance of the transparent conductive coating with respect to light wavelength. Engineering drawing 1

Claims (1)

[Claims] α) A transparent film-forming paste characterized by separately preparing a paste containing an organic tin complex as a main component and an organic antimony compound* bath solution, and mixing the two to form a film-forming paste. A method for producing a paste for forming a conductive film. 3) In claim α), the organotin complex is [dimethyltin acedope (CH3) 18n
A method for producing a film-forming phase paste using (acac) 1 as an organic antimony compound.゛ ′